Cut down on calories by following the pistachio principle: Leave your shells or wrappers in a pile and you won’t eat as much.
According to a new study published in Appetite, snacking on in-shell pistachios can help decrease the amount of calories you consume by more than 40 percent. Researchers at Eastern Illinois University monitored students who consumed either in-shell pistachios or shelled pistachios during class. When the lesson was over, students who snacked on shelled nuts consumed close to 211 calories, while those who ate the in-shell kind ate only 125 calories.
In a second study, researchers found that people who kept pistachio shells on their desk after eating them for 2 workdays consumed 22 percent less than those who emptied their shells throughout the day.
That’s because the shells serve as a visual cue to remind you how much you’ve already eaten, and being able to keep track of how much you consume makes it easier to control portion sizes, says lead author James Painter, Ph.D., R.D., Chair of the School of Family and Consumer Sciences at Eastern Illinois University.
“Anything that is individually packaged that you have to open up will decrease your consumption,” says Painter. “This is why the pistachio is called the ‘skinny nut’—opening the nut slows you down, allowing your internal cues to catch up to your visual cues, thus people are fooling themselves full.”
Here’s how to apply the pistachio principle to your favorite foods: If you’re craving something sweet, choose Hershey’s Kisses over M&Ms or, if you’re not the chocolate type, Starburst over Skittles. If you’re in the mood for something salty, opt for mini-bags of pretzels instead of purchasing the big bags at the store.